Method of casting with the aid of gaseous pressure mediums



Feb. 26, 1929. 1,703,739

w. KLEPSCH METHOD OF CASTING WITH THE AID OF GASEOUS PRESSURE MEDIUMS Filed Aug. 8, 1924 4 In v 61% $01 M11 Lapse),

fltty Patented Feb. 26, 1929.

UNITED STATES WILHELM KLEPSCH, OF VIENNA, AUSTRIA.

METHOD 0] CASTING WITH THE AID 0F GASEOUS PRESSURE MEDIUMS.

Application fled August 8, 1924, Serial No. 730,972,

Methods of casting with the aid of compressed air are already known, in which the outlet leading from the pressure space to the mold is continuously submerged in the molten metal or metal-bath. However by these known methods the outlet is frequently destroyed and thus leads to annoying interruptions in the working. Therefore it has been proposed already to arrange the outlet and metal-bath movable with respect to one another, and to allow the former to be submerged in the metal-bath during the casting operation only. Homogeneous castings cannot be produced accor ing to these known methods, as it is not possible to remove the gas from the metal, and air blisters will be present in the castings.

Also methods are known in which the casting operation is carried out with the aid of compressed air and of a vacuum in order to produce a homogeneous casting which is free of any gaseous contents as far as possible. However by these known methods the operation is very complicated, slow and expensive and continuous break-downs are the result, as either a number of shut-oil members and compensating members are employed or the melting-pot has to be rocked.

According to the present invention the mold and the pressure space surrounding the metal-bath are evacuated if the outlet is not yet submerged in the metal-bath, subsequently the outlet submerged in the metal-bath and thereafter pressure is applied.

By this method the pressure space and mold or vice versa are positively evacuated before the molten metal enters the mold, whereby a homogeneous casting is produced which, as far as possible, does not contain any gas, and at the same time the outlet cannot be destroyed as the latter is not continuously submerged in the metal-bath.

By the method according to the present invention a homogeneous casting can be quickly and inexpensively produced which, as far as possible, does not contain any gas, and any break-downs in the operation are reduced to a minimum.

Figs. 1, 2 and 3 of the drawings illustrate by way of example t-he individual steps of the method according to the present invention.

Fig. 1 shows the arrangement before the casting operation. The mold 8 is disposed at one side of a plate 9 above the outlet 2, and the mold is enclosed in a casing 10, which'is tightly fitted to the plate 9. A pipe 6 passes and in Austria August 9, 1928. from the casing 10 to a convenient vacuumdevice. pipe 7 passes from the pressure space 1, disposed at the other side of the plate t), to the vacuum-device. A vessel 3, containmg the metal, is arranged on a slide 4 in such a manner, that the outlet does not extend into the metal-bath, and the slide 4 is tightly packed at 11.

Fig. 2 shows the arrangement in the position before applying the pressure medium. In this position the outlet 2 projects into the metal-bath.

Fig. 3 illustrates the arrangement in the position after the casting operation, the latter being carried out in the following manner:

The metal in the vessel 3 is melted in the pressure space 1 or the vessel 3 is filled with molten metal and inserted in the pressure space 1, and subsequently the latter is hermetically closed-up. Now by means of the pipe 6 the air contained in the casing 10 is exhausted and the vacuum produced thereby extends over the mold 8, the outlet 2 and the pressure space 1. If desired the mold 8 ma be provided with grooves or holes, which establish communication between the vacuumspace 5 and the outlet 2.

In case the vacuum-gauge (not illustrated) indicates that the desired vacuum has been produced in the pressure space 1 and in the vacuum-space 5, the vessel 3 is lifted b means of the slide 4 until the outlet 2 extends into the metal-bath (Fig. 2). Now pressure is applied through the pipe 7, whereby the metal is forced through the outlet 2 and into the mold 8.

Without limiting the scope of the invention the casing 10 may be dispensed with, in which case the vacuum-pipe 7 extends into and communicates either directly with the mold 8 or with the pressure-space 1. In the latter case the pipe 6 is shut-off before applying pressure.

I claim 1. The process of casting metals which comprises maintaining a body of molten metal adjacent to but not in communication with a mold, putting the mold and space about, and in contact with, the body of molten metal, under sub-atmospheric pressure, establishing a liquid communication, also under sub-atmospheric pressure, between the mold and the body of metal and thereafter subj ecting the space about and in contact with the body of metal to a pressure in excess of thatwithin the mold whereby the molten metal is caused to flow into the mold.

An apparatus for casting metals with theaid of a pressure medium, comprising a vessel capable of being evacuated, a container for maintainin molten metal disposed in saidvessel, a mold, a pipe communicating with said mold and with said vessel and protruding into said vessel, said pipe terminating in said vessel at a point above said molten metal container, means for evacuating said mold, said pipe, and said vessel, means for changing the position of said container whereby said pipe is caused to terminate in said container, and means for introducing a gaseous pressure medium into said vessel and into contact with said container.

3. The process of casting metal as claimed in claim 1 in which the subatmospheric pressure in the mold is positively maintained or increased after the molten metal has been subjected to the higher pressure.

In testimony whereof I have signed my name to this specification.

WILHELM KLEPSCH. 

